JPS595583B2 - N-sulfinyl carbamate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a class of novel carbamate insecticidal compounds and intermediates thereof.

(Insecticides in this specification are insecticides in a broad sense,
Not limited to insecticides. That is, it is an exterminator for agricultural crops and domestic pests that has insecticidal, nematicidal, acaricidal, and larvicidal activities. ) More particularly, the present invention relates to N-sulfinyl carbamates useful as insecticides or insecticide intermediates.

A wide variety of carbamate insecticides have been described to date.

For example, FulcutO and Bla
US Pat. No. 3,997,549 to ck) discloses N-arylsulfenylated derivatives of benzofuranyl methyl carbamates as effective insecticides. U.S. Pat. No. 4,006,231 to Black and Fulcut O discloses N-aminosulfenylated derivatives of carbofuran as effective insecticides.
and U.S. Patent No. 3843 to BrOwrl.
No. 689 discloses the preparation of N-methyl or N-phenyldithiocarbamates from N-chlorothiocarbamates as insecticides. The insecticidal compounds of the present invention have high levels of insecticidal activity and improved toxicity to mammals.

The activity is approximately equal to that of the carbamate insecticides from which the compounds are derived, but the toxicity to mammals is generally substantially lower. The sulfinyl carbamate of the present invention has the formula, where R2 is an aryl group of the formula (wherein Ra is lower alkoxy, R
b is lower alkyl.

); or an imino group of the formula RgRhC=N- (wherein Rg
is hydrogen or alkyl of 1 to 4 carbon atoms; Rh is alkylthio or alkylthioalkyl of 1 to 4 carbon atoms; and R3 is hydrogen or alkyl of 1 to 4 carbon atoms;
R6 is alkyl of 1 to 4 carbon atoms, R7 is lower alkyl, an aryl group of the formula → (wherein Ra is as defined above), or RgRhC-
It is characterized by being an imino group of N- (wherein Rg.Rh is as defined above).

Thus, it will be appreciated by those skilled in the art that the present invention includes, for example, molecules containing any two of such carbamates linked by a sulfinyl group. It is understood that the present invention includes and is applicable to virtually any number of N-sulfinyl derivatives of known insecticide carbamates, including others well known to those skilled in the art, including N-sulfinyl derivatives of insecticide carbamates.

N-chlorosulfinyl carbamate is prepared by reacting a carbamate starting material with thionyl chloride according to the following general reaction scheme.

The reaction is often carried out without solvent and with heat to produce the corresponding N-chlorosulfinyl derivative and HCl. The reaction is generally conducted at a temperature ranging from about 60 to about 100°C. An excess of thionyl chloride is commonly used, preferably up to about a 50% molar excess. Hydrogen chloride is generated during the reaction and excess thionyl chloride is removed. The reaction of the carbamate starting material with thionyl chloride can also be carried out in a solvent; polar non-hydroxyl or non-polar organic solvents that do not react with thionyl chloride are suitable.

Examples of suitable solvents are tetrahydrofuran, dichloromethane and hexane. An acid or hydrogen chloride acceptor is added to aid the reaction.

The preferred acid acceptor is pyridine, although other tertiary organic amines can also be used as acid acceptors. ．． These include dimethylaniline or diethylaniline, as well as numerous other acid acceptors well known to those skilled in the art. Reactions using organic solvents and acid acceptors can be carried out from room temperature to elevated temperatures of about 60°C. Stoichiometric molar amounts of thionyl chloride and carbamate are used when using organic solvents and acid acceptors.

However, if desired, a small molar excess of thionyl chloride, for example up to about a 10% molar excess based on the carbamate, can be used. Approximately equimolar amounts of acid acceptor and carbamate starting materials are generally used. However, a molar excess of acid acceptors e.g.
Up to a 5% molar excess may be used if desired. The following reaction illustrates the conversion of N-chlorosulfinyl carbamate.

Without isolation, the N-chlorosulfinyl carbamate ester can be reacted in situ with the above-mentioned reactants in the presence of an equimolar amount or molar excess of an acid or hydrogen chloride acceptor to form an insecticide (pesticide). N-sulfinyl carbamate esters, , V, or are produced.

The temperature of the reaction medium will vary depending on the reactivity of the particular reactants used and the reaction system, but may generally be carried out at a temperature of about 0°C to 70°C, preferably 10°C to 60°C. Example 1 is the N-N-sulfinyl dicarbamate formula 1 of this invention.
The preparation of the compound of

The compounds can be symmetrical or asymmetrical with respect to the sulfinyl sulfur. In the symmetrical compound, the above R7 is R
2 and R6 is the same as R3.

These symmetrical compounds are easily prepared in a one-step process according to the following general reaction scheme. It is done using.

The carbamate ester product was prepared using 2 moles of carbamate ester starting material per mole of thionyl chloride at 0°C.
to 50°C, preferably at room temperature (20°C), using an acid acceptor such as triethylamine in a ratio of about 2 moles per mole of carbamate starting material, or slightly greater;
It can be produced in high yield. Symmetric N-N'-sulfinyl dicarbamates can also be made by the following reaction formula.

This procedure is more inconvenient than the direct reaction of thionyl chloride with carbamates.

However, it may be useful if R2 is unsubstituted or substituted with a thionyl chloride-sensitive functional group such as a monoalkyl-substituted amide or an aromatic or aliphatic amine. Unsymmetrical N-sulfinyl dicarbamates are made by reacting N-chlorosulfinyl carbamates (Q) with alkyl, aryl or oxime carbamate starting materials according to Scheme (C) above.

Example 1 illustrates this method of preparation. Example 1 Synthesis of S-methyl N-[[N-methyl-N-[(N″-ethyl-N'-n-propoxycarbonyl)aminosulfinyl]carbamoyloxy]]thioacetimidate 20 grams of anhydrous dichloromethane S-methyl N- in
In a solution of (N-methylcarbamoyloxy)thiocetimidate (3.3 V. 0.02 mol) 4.3 t of propyl(ethyl)(chlorosulfinyl) carbamate (made from propylethyl carbamate and thionyl chloride), Boiling point is 65-69℃ at 0.5W!l) and 1.6V
(0.02 mol) of anhydrous pyridine was added.

The mixture was stirred for 12 hours at room temperature. Ether (100
m1) was added and the mixture was washed three times (30 d each) with water. The ethereal solution was dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. A sample of the oily residue was purified by preparative thin layer chromatography using a mixture of ether-hexane (3:1) as the developing solvent. CllH2
The analysis calculated for lN3O5S2 is carbon, 38.
92%: hydrogen, measured value at 6.23%: carbon, 38.38
%; hydrogen, 5.78%;

Examples 2-7 shown in Table 1 further illustrate the N-N'-sulfinyl dicarbamates of the present invention. The insecticidal compounds of this invention are formulated with conventional carriers including additives, fillers used in the manufacture of insecticidal compositions. Therefore, the toxins of this invention are generally not applied at full strength, as are most insecticidal agents, and the active ingredients are combined in recognition of the accepted fact that the formulation and mode of application of the toxin can affect the activity of the substance. Commonly used adjuvants and carriers are included to facilitate the dispersion of the carrier. The compounds of the invention can be prepared into liquid concentrates by solution or emulsion in suitable liquids such as organic solvents, and with talc, clay and other known solid carriers used in pesticide technology. A solid concentrate is created by mixing.

These concentrates are compositions containing from about 5 to about 95% toxicant and other inert materials including dispersants, emulsifiers, and wetting agents. These concentrates are diluted for practical use with water or other liquids for liquid spray solutions or with additional solid carriers for application as powder or granular formulations. In the dilutions commonly used for application, the concentration of toxicant ranges from about 10% down to about 0.001% depending on the means available for application.

Many variations of spray and powder compositions in this art may be used by substituting the compounds of this invention into compositions known or apparent in the art. The compounds of the invention are also applied without further dilution. For example, powder
It can be made into compositions such as powders and granules. These ready-to-use formulations generally contain from about 0.1% to 50% toxicant, preferably from about 1.0 to about 45%. The insecticidal compositions are formulated and applied with other active ingredients, including other insecticides, nematicides, acaricides, fungicides, plant growth regulators, fertilizers, and the like.

It will be apparent that effective amounts and concentrations of the carbamate ester compounds of this invention should be used in pharmaceutical applications. Two insect species per representative compound of the invention,
Namely, home fly: Muscad Ome
stica) and mosquito larvae: Charetschus pipiens (C
alexpipiens) was tested for insecticidal activity.

Make a 1% concentrated solution of the raw material of each test compound in acetone, dilute the solution with acetone, and add 0.001 to 0.1%
The concentration was set to The fly was treated locally on the notum (the dorsal part of the ring segment on the abdomen of the insect) with 1 μl of each diluted acetone solution. After application, insects should be heated to 60'F
(15.6°C) was maintained at a constant temperature. Percentage mortality was counted 24 hours after application. Larvicidal activity was determined by applying 1 TfL of an acetone solution in 100 ml of water containing 20 mosquito larvae at the third instar (period between molting and ecdysis of the insect larvae) stage. Decided.

Results are expressed as LD5O in μt/t for house flies and LC5O in Ppm for mosquito larvae. Toxicity to supplements was determined on Swiss white mice. Test compounds were administered orally using corn oil as a carrier. The results are given as LD5O in ~ of the compound per kg of body weight.

Test data for the N-sulfinyl carbamates of the present invention are summarized in the table.

In the table, the term "LD5O" refers to the dose required to kill 50% of the test animals and the term "LC5O" is the concentration required to kill 50% of the mosquito larvae. When interpreting the values in the table, the values for LD and O for house flies,
The lower the value for LC5O against mosquito larvae, the greater the insecticidal power or toxicity of the individual compound. On the other hand, the higher the LD5O value for 20-day mice, the lower the toxicity to mammals and the greater the safety of the compound in supplementation. Referring to the table, the compounds of this invention possess insecticidal activity relatively comparable to that of the carbamate esters on which they are based, but with substantially reduced mammalian toxicity and thus substantially reduced mammalian toxicity. jIt has safety.

The table tabulates the physical constants of the compounds shown in the table.

Claims (1)

[Claims] 1 In the formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼, R^2 is the aryl group of the formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ , (wherein Ra is lower alkoxy and Rb is lower alkyl in the above formula) or formula R
gRhC=N- imino group (wherein Rg is hydrogen or alkyl having 1 to 4 carbon atoms, and Rh is an alkyl group with 1
alkylthio or alkylthioalkyl of ~4 carbon atoms); R^3 is alkyl of 1 to 4 carbon atoms; R^6 is alkyl of 1 to 4 carbon atoms; R^7 is a lower alkyl, an aryl group of the formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (in the formula, Ra is as defined above)
, or an imino group of RgRhC=N-, where RgRh is as defined above. 2. The compound according to claim 1, wherein R^7 is the same as R^2. 3. A compound according to claim 1, characterized in that R^7 and R^2 are different, 4. At least one of R^2 and R^7 is a formula ▲ has a mathematical formula, chemical formula, table, etc. ▼ or ▲ The compound according to claim 1, which is a substituted aryl group represented by ▼, which includes mathematical formulas, chemical formulas, tables, etc. 5 At least one of R^2 and R^7 has the formula RgRhC=
The compound according to claim 1, which is an N-imino group.